1. Field of the Invention
This invention relates to a solid golf ball comprising a solid core and a two-layer cover, and more particularly, such a golf ball which is improved in feel at no sacrifice of flight performance and durability.
2. Related Art
Golf balls having a variety of constructions are available today on the market. The majority of commercial golf balls are either two-piece solid golf balls comprising a rubber-based core and a cover composed of ionomer resin or the like, or thread-wound golf balls comprising a thread-wound core obtained by winding rubber thread about a solid or liquid center, and a cover formed over the core.
Most golfers of ordinary skill use two-piece solid golf balls because of their excellent flight performance and durability. However, these balls have a very hard feel and are poor in control due to the rapid separation of the ball from the club head. For this reason, many professional golfers and skilled amateurs prefer using thread-wound balls to two-piece solid balls. Yet, although thread-wound golf balls have a superior feel and control, their distance and durability fall short of those for two-piece balls.
Thus, two-piece solid golf balls and thread-wound golf balls today provide mutually opposing features, and so golfers select which type of ball to use based on their level of skill and personal preference.
In order to produce solid golf balls presenting a feel close to that of wound golf balls when hit, we made a number of proposals using three-piece solid golf balls comprising a solid core, a cover inner layer and a cover outer layer, as disclosed in JP-B 8301/1995, JP-A 24084/1995 and JP-A 10358/1997. These patents disclose golf balls wherein the cover outer layer is formed harder than the cover inner layer, and the balls are designed so as to acquire a lower spin rate upon shots intended for distance like driver shots.
These balls are advantageous in flight distance, but they are difficult to stop due to the low spin structure.
By contrast, many proposals were also made on golf balls which are improved in control, as disclosed in JP-B 4110/1993 and JP-A 24085/1995. These golf balls are characterized in that the cover inner layer is formed harder than the cover outer layer. It is intended to increase spin by softening the cover outer layer to increase the friction of the ball with the club face. Despite the advantage of increased spin, these golf balls, however, sometimes fail to increase the flight distance because of the soft cover outer layer inviting a loss of resilience.